OFFSET
0,4
COMMENTS
Or, number of self-dual 2-monotonic Boolean functions of n or fewer variables.
Agrees with A001532 for n <= 8 but then diverges.
The value for n=10 was calculated with BDD techniques; all solutions are characterized by a binary decision diagram with 30011986 nodes.
The value for n=11 was calculated by Minfeng Wang in May 2012 (see [Hausmann & Rodriguez]). The news was published by J.-C. Hausmann (2015). - Fabián Riquelme, Mar 19 2018
For n from 1 to 9, a(n) agrees with the number of directed zero-sum games with n players in Table 1 of Krohn and Sudhölter. - Peter Bala, Dec 16 2021
REFERENCES
D. E. Knuth, The Art of Computer Programming, Vol. 4, Section 7.1.1 (in preparation).
LINKS
Jean-Claude Hausmann, Counting polygon spaces, Boolean functions and majority games, arXiv preprint arXiv:1501.07553 [math.CO], 2015.
Jean-Claude Hausmann and Eugenio Rodriguez, The space of clouds in an Euclidean space, Corrections and additional material, 2014.
I. Krohn and P. Sudhölter, Directed and weighted majority games, Mathematical Methods of Operation Research, 42, 2 (1995), 189-216. See Table 1, row 4, p. 213; also on ResearchGate.
S. Muroga, T. Tsuboi and C. R. Baugh, Enumeration of threshold functions of eight variables, IEEE Trans. Computers, 19 (1970), 818-825.
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Don Knuth, Aug 17 2005
EXTENSIONS
a(10) from Don Knuth, Feb 06 2008
a(11) from Fabián Riquelme, Mar 27 2018
STATUS
approved